greddygalant

iTrader: (3)

Hood is vented, car overheats at part throttle over the course of 5 laps or so of no more than 10 psi too. It also now overheats under light load on the freeway. This led me to believe it was the head gasket. Head ckecked out and gasket was replaced as well as wp, thermostat, etc. Freeway overheating was resolved slightly but it still ran around at 200 after a few highway pulls which it never did before. I've pressure tested the coolant system and didn't see a drop in pressure from 20 psi over 20 minutes.

aidandj

iTrader: (5)

So the only changes between the car overheating and not overheating was the new turbo and 6 months?

Thats really really weird. I'd try a different radiator next.

jmann

Hey Martin Right head gasket?

greddygalant

iTrader: (3)

Yep 99 head gasket. Changes are new turbo, better ducting, smaller intercooler, better piping.

aidandj

iTrader: (5)

The only thing I can think of would be the intercooler is more dense and not allowing as much air through as the old unit did.

Otherwise sounds like something wrong in the engine.

greddygalant

iTrader: (3)

I'm leaning towards engine as well I just don't know what short of a full tear down and block inspection

jmann

Martin You put power steering back on, did you modify the by-pass housing for the lower hose? Could it be sharper bends or something? Just grasping at straws here. I doubt it is the block but it is very puzzling.

greddygalant

iTrader: (3)

Mixing manifold is still flipped, cooling system layout has not changed at all since last year, power steering addition changed nothing there

HHammerly

iTrader: (3)

Before yanking out the motor I would put a high pressure radiator cap, tap into one of the coolant barb fittings for the oil cooler lines on the back of the head and presurize the system to make sure it is holding the correct pressure per the cap you have on the radiator, if not start looking for the place where the pressure is escping like cap, loose hoses heater core etc. the system does not reach your cap rated temp the water will boil on the cylinder jackets and head and the engine will overheat.

greddygalant

iTrader: (3)

Coolant system has been pressure tested with no leaks it has a high pressure koyo cap on it already. I swapped caps before doing the head gasket but that changed nothing, unless I had 3 bad caps in a row.

jmann

Martin Any chance you have a rag or paper towel in a hose or tube somewhere to keep stuff out while the engine was a part? Do you have inner springs in the rad. hoses to keep them from collapsing when hot?

curly

iTrader: (25)

He should probably mention the new sand paper finish on Pistons 1&2, and the ~dozen or so pit marks on #4. That's my suspicion. Anything but a smooth surface generates a lot of heat, so says the theory. It does run warm at cruise. Shouldn't hit over 180 just cruising around in 68 degree weather, it's sitting around 195-200. Hit steady boost and it sky rockets.

hornetball

iTrader: (4)

I'm running the FAB9 IC on the Silver car. That intercooler mounts really far forward, it's a really good air blocker. I'm not overheating on the highway, even with AC on. It does run warm though, around 215-220. When I drop the top and turn the AC off, it's 195. I have to baby it when I take it to the track, and I'm only around 200HP give or take. Then again, I'm in N. TX (along with Gary from TDR), not Oregon.

Guess I wasn't much help, but everything else you did helps cooling except for the intercooler. I'm wondering if that was the difference?

jmann

Josh I have 2 pistons with pits in them running 19 psi with no issues as far as overheating goes. If there is no restricted flow issues I would think hornetball maybe has found the issue. Try the old intercooler?

greddygalant

iTrader: (3)

Could that really be the cause? My old intercooler was much taller and wider basically covered the entire surface of the radiator, but it was mounted much further back than the fab 9 unit. I'm just at a huge loss ar this point. I'm considering pulling the IC off and running a straight pipe with 2 couplers to bridge the gap to do some testing. Would really suck if this IC was the issue considering I gave up a larger free unit for this piece.

aidandj

iTrader: (5)

That's honesty a way easier test than stripping down the block.

psyber_0ptix

iTrader: (4)

I thought the more distance away from the heat exchangers, the better for flow? What's this too far nonsense?

curly

iTrader: (25)

In for Laz's first V-mount setup. Also I don't see how that would explain the "light switch effect" as I call it, temps climb dramatically with boost.

greddygalant

iTrader: (3)

Gonna get some pipe and experiment I guess. Will report my findings and go from there.

hornetball

iTrader: (4)

One other thing I'll mention is that I'm running the "Stage 1" FAB9 IC. It still leaves a bit of a gap between the top and the plastic bumper support to flow some air to the condenser/radiator/oil cooler that doesn't have to go through the core. If you're running their "Stage 2," I honestly have no idea how you would have any cooling beyond really low intake temps.

I've seen posts from Braineack talking about switching from a dense bar/plate IC to a cheaper tube type IC to get better radiator performance. Sixshooter, another hot climate guy (FL), has posts about trimming away the plastic bumper support to promote air flow over an IC into the radiator. Assuming your "tube" experiment finds a smoking gun, then these are both options for you.